| st1 .refs ∩ st .refs = ∅, r ∈ st .refs, junkrefs(str, r ' + refs0, st[r -- _type] .type, st1 ∪ st), r ∈ st1, r -- _type ∈ st, r ∈ st .refs ⊦ st = ∅, junkrefs(str, r ' + refs0, st1[r -- _type] .type, st1), ∃ refs. refs ≠ [] ∧ refs .first = r ∧ junkrefs(str, refs, st1[refs .first -- _type] .type, st1) |
⊦ r ∈ st ↔ r ∈ st .refs
[[CONCRETESIMPRULES : ([CSIMPSEQ : ⊦ (rset ∩ rset0) ∩ rset1 = rset ∩ rset0 ∩ rset1], [CSIMPSEQ : ⊦ rset ∩ rset0 = rset0 ∩ rset], [CSIMPSEQ : ⊦ rset ∩ rset0 = ∅ ∧ r ∈ rset → (¬ ¬ r ∈ rset0 ↔ false)])], [EXTRATERMS : (st1, r)]]